In the institutional laundry field, such as for hospitals or hotels, the large scale, industrial washing machines process laundry in three general steps or cycles; a flush cycle, a wash cycle, and a bleaching cycle. The linens are run through a flush cycle (also referred to as a pre-wash or first wash cycle), where large dirt and loose components (such as debris and bodily waste) are removed from a load of linens as the flush solution is discharged from the washing machine. Then, the linens are run through a wash cycle, followed by a bleaching cycle. Rinse cycles may be interposed between the washing and bleaching cycles, and after the bleaching cycle. One such washing machine is known as an extractor. The extractor has one large tub into which the soiled linens are placed, and each cycle is then conducted in sequence using the same tub, with liquid introduced as necessary for each cycle, and the liquid used during the cycle removed before the next cycle begins. Another industrial washing machine type is a tunnel or continuous batch washer (CBW). In a CBW, linens pass from stage to stage of the tunnel where each cycle is conducted, typically with liquid from a subsequent stage. Thus, a first stage receives the soiled linen, liquid is introduced, which may be the remaining liquid from the next or subsequent stages, and the flush cycle conducted. The liquid from the flush stage, along with the heavy soil, is discharged, and the now flushed laundry is moved to the next stage(s) or cycle(s). This sequence continues through wash and bleach cycles, as well as any intervening or subsequent rinse cycles, until the cleaned linen load is available at the last stage. Thus, a first stage receives the soiled linen, liquid is introduced, which may be the remaining liquid from the next or subsequent stages and/or fresh water, and the flush cycle conducted.
While the foregoing types of industrial washing machines, and their operational processes are well entrenched in the institutional laundry field, certain stains have been found difficult, if not impossible, to avoid. Two particularly challenging stains arise from the use of chlorhexidine and avobenzone in healthcare and hospitality settings, respectively. Chlorhexidine is used extensively in the healthcare field in such products as Habiclens®, Savinox Plus®, Surgiprep-CHX™, Hibiscrub™, or Dexiden™. In a hospital or other healthcare setting, the chlorhexidine-containing products soak into various linen items used by patients and medical care givers, such as gowns, sheets, scrubs, and other similar linens. Avobenzone is used as a sunscreen and, so is similarly present in linens and robes after they have been used in hospitality facilities such as hotels and motels, for example. Chlorhexidine and avobenzone, when present, tend to stain the fabric materials with which they come into contact, and these stains are difficult to remove.
Typical laundry processes are considered insufficient to adequately deal with staining from chlorhexidine or avobenzone. Instead, the typical laundry process merely masks or fades the stain. That is not a desirable result.